Canine Addison’s disease, otherwise known as hypoadrenocorticism, is the flip side of the far more common canine Cushing’s disease. With Cushing’s, the adrenal glands overproduce the hormone cortisol, but with Addison’s, these glands produce too little cortisol and aldosterone (another hormone).
Cortisol is often referred to as the “stress hormone” because it helps the body regulate the effects of stress. It does a lot more, though, including helping your assistance dog regulate her blood glucose levels, appetite, and weight; stave off infections; maintain healthy function in all her organs; and more. Aldosterone’s most important job is regulating levels of the electrolytes potassium and sodium, which in turn affect heart rate and other essential biological functions.
Under-production of any hormone can have a variety of harmful effects. A guide, hearing, or service dog suffering from Addison’s disease experiences symptoms that can be dangerous, that detract from her quality of life, and that interfere with her ability to reliably meet her working responsibilities.
What Causes Canine Addison’s Disease?
This isn’t all that common an endocrine disorder in dogs, but it tends to affect young to middle-aged dogs. A few breeds commonly trained as assistance dogs have a genetic predisposition increasing their risk of developing Addison’s: notably, Labrador retrievers and standard poodles.
Various factors may cause Addison’s disease. Most often, it’s due to an autoimmune condition in which the immune system attacks and damages the adrenal glands. Other damage to the glands, as from an infection or trauma, can also cause hypoadrenocorticism. A tumor on the adrenal glands or the pituitary gland (an important regulator of hormone production) can also cause this disorder.
If your assistance dog has the more common Cushing’s syndrome and is being treated with medication to lower cortisol production, this too can cause Addison’s. This treatment requires regular monitoring to ensure the dosage is properly regulating hormone production; sometimes, cortisol production is reduced too much, making Addison’s a side effect of treatment. Addison’s can also result from abruptly stopping long-term administration of corticosteroids, though it’s highly unlikely any dog with a condition managed in this way would be working as a guide, hearing, or service dog.
What Are the Main Signs and Symptoms of Addison’s Disease?
The primary symptoms of Addison’s disease, which may be intermittent, include:
- Weakness and/or lethargy
- Loss of appetite
- Weight loss
- Increased thirst and urination
- Blood in stool
- Shaking episodes
- Hair loss
- Low blood pressure and/or heart rate
- Low body temperature
- Pain in the abdomen
A sudden bout of severe vomiting or diarrhea and weakness, possibly accompanied by collapse, is known as an Addisonian crisis in affected dogs. This is a medical emergency requiring immediate veterinary intervention.
How Is Addison’s Disease Diagnosed in an Assistance Dog?
The symptoms of Addison’s disease aren’t all that specific, and combined with the fact that it’s not seen frequently in dogs, the possibility is easily overlooked. Provide your vet with details about symptoms and changes you’ve seen, when they first appeared, how they’ve progressed, and any other information.
Blood tests and urinalysis measure levels of electrolytes and other compounds, and these results provide useful clues for diagnosing hormonal imbalances like Addison’s disease. An ACTH stimulation test is the best way to confirm Addison’s. This involves administering ACTH, a hormone whose production is closely related to adrenal function, and observing the response.
Imaging tests may be used to rule out other explanations of your assistance dog’s problems, as well as to check for tumors, glandular damage or enlargement, and other concerns.
How is Canine Addison’s Disease Treated?
Treatment for Addison’s disease partially depends on the cause. Underlying problems like an autoimmune condition or tumor require treatment. Hormone levels are boosted with synthetic supplements that must be taken for life, assuming the Addison’s is not temporary, as from stopping use of corticosteroids. An oral medication provides cortisol, while desoxycorticosterone pivalate is an injectable medication typically given every 3 to 4 weeks to replace aldosterone. Some dogs don’t do well on this injected medicine and receive an oral alternative.
Many pet dogs go right back to life as normal with treatment, but of course it’s not such a simple matter for working dogs. A lot depends on what other treatments were needed, whether your dog regains her full energy and enthusiasm, and whether she doesn’t experience any lasting or side effects. You’ll need to honestly and objectively gauge your assistance dog’s general health and mood and consult your vet.
Disclaimer: The information contained in this article is general information only. Please consult a qualified veterinarian regarding all medical conditions for your assistance dog.